Toaster timer having external adjustment

ABSTRACT

A bimetal timing mechanism having first and second externally actuated adjustment means that change the orientation of the bimetal relative to the release latch means effective thereby, respectively, to factory calibrate the mechanism to its particular use, such as in a toaster for timing the toasting cycle, and to accurately vary this factory-set cycle control for individually satisfying he user&#39;&#39;s preferences.

United States Patent lnvenlor Franklin C. Hlturoth Centervtlle, IowaAppl. No 18,256

Filed Mar. 10, 1970 Patented Aug, 17, 1971 Assignee McGraw-EdisonCompany Elgln, lll.

TOASTER TIMER HAVLNG EXTERNAL ADJUSTMENT 9 Claims, 7 Drawing Figs.

U.S.Cl..v 99/329 Int. Cl. l l l l l a l A47j 37/08 Field of Search... 199/329,

l 561- References Cited UNITED STATES PATENTS 3,029,725 4/1962 Parrv99/329 3,175,482 3/1965 Olson... 99 329 3,361,053 1/1968 Jepson et al.99/329 3,418,917 12/1968 Sato 99/329 3,452,670 7/1969 Huck et al 99/329Primary Exumlner--Billy J Wilhite Arlorney-Charles F Lind ABSTRACT: Abimetal timing mechanism having first and second externally actuatedadjustment means that change the orientation of the bimetal relative tothe release latch means effective thereby, respectively, to factorycalibrate the mechanism to its particular use, such as in a toaster fortiming the toasting cycle, and to accurately vary this factnry-set cyclecontrol for individually satisfying he users preferences.

v v v v v v v v s a iv v v PATENTEU Am: 1 11971 I 3599.312

sum 1 OF 2 1 h g -95 I 1 r? 0 I 78 xp l'anlgn/ 1 M j TOASTER TIMERHAVING EXTERNAL ADJUSTMENT The Henry L. Olson US. Pat. No. 3,175,482discloses a bimetal timing mechanism that is particularly effective foraccurate control of the cooking cycle of a electric appliance, such as atoaster. The timing mechanism is unitary and thus canbe fabricated andadjusted in its entirety at one location andthen with few connectionssecured in place on the toaster chassis. The bimetal element is heatedboth by its separate heating element and the appliance heater, and thusis influenced by heat buildup. This compensates automatically to'varythe cycle length as between the initial and successive operatingcycles to give the desired toast color. The timer bimetal deflects underthe heating influence of both heating elements to release a first latchthat effectively deenergizes the bimetal heating element only, whereuponthe bimetal cools slightly to release a second latch that deenergizesthe toaster heating elements. Gauges are used to factory calibrate thetiming mechanism to the particular toaster appliance and a singleextemal'adjustment is provided for customer fine tune or preferencecontrol of the cycle. Since each toaster is actually operated afterfactory calibration and the resulting toast color compared to anaccepted standard, if the standards are not met, the toaster must becooled, recalibrated, and retested. This special handling, on improperlycalibrated appliances, is not only time consuming but, also appreciablyadds to the overall cost of the toaster. I

In the subject invention, first and second externally actuatedadjustment means are provided for varyingthe bimetal deflection requiredto trip the latch means to provide both accurate factory calibration ofthe timingvmechanism to the particular appliance but also individualpreference adjustments. Consequently," is now possible by varyingoneadjustment means to calibrate the timing mechanism .to the toaster onthe testing cycle without later disassembling or retesting the toasterwhile further with a second adjustment means to allow fine-tuneindividual control by the user. I

Accordingly, a main object ofthis invention is to provide for use 'in acooking appliance like a toaster, a bimetal timing mechanism havingfirst and second adjustment means, each externally actuated, suited forfactory calibration of the timing mechanism to the appliance and forofi'ering individual preference control to the user.

This and other objectsof the invention will be more fully understoodafter reviewing the following specification, including the drawings,wherein:

FIG. 1 is a perspective view of a toaster having a bimetal timingmechanism forming a part thereof, with part ofthe toaster case beingbroken away for convenience of disclosure;-

FIG. 2 is a perspective view of the underside of the timing mechanismused with the disclosed toaster, and showing a preferred embodiment ofthe particular invention;

FIG. 3 is a rear elevational view of the timing mechanism shown in FIG.2;

FIG. 4 is a top plan view of the timing mechanism shown in the previousfigures;

FIGS. 5 and FIG. 6 are elevational views, as seen from the left of FIG.4, showing the timing mechanism in different operative views; and

FIG. 7 is a bottom plan view of the timing mechanism disclosed in theprevious figures.

Referring to FIG. I, the illustrated toaster 10 includes a base 12 ofphenolicor other insulating material supporting thereon a chassis l4 andoverlying case 16. The chasses l4 and case 16 each is formed of a sheetmaterial construction in a typical manner having bread-receiving slots18 that open to between opposing heating elements 20. A bread-holdingarm 24 extends from between the heating elements through a slot 26 inthe toaster chassis l4 and is secured to carriage 28. The carriage 28rides on rod 29, and spring 30 biases the carriage to the uppernontoasting position while lever 32 extended through case slot 33provides for manually lowering the carriage to the toasting position. Atiming mechanism 34 has lock 35 that engages carriage hook 36 to holdthe carriage in the lowered toasting position, while the lock is movablealso to release the carriage for return movement to the elevatednontoasting position. Air-snubbing device 37 dampens'the upward movementof the carriage. When the carriage is in the lower toasting position, apair of leaf contacts 38 are closed through the action of lever 39pivoting at 40and abutted at 4l by the carriage which provides power tothe toaster heating elements 20 The bimetal timing mechanism 34 shownhas a generally L- shaped base 44 which is secured tothe toaster chassis14 as by screws 46. Upstanding spaced ears 50 formed from the base 44pivotally support therein element 52 on which the lock 35 previouslymentioned is located, and spring 53 tends to rotate the lock element tothe released position (FIG. 3). When the carriage is lowered by theoperating lever 32, a part 54 thereof (FIG. 1) engages the element 52 topivot it about the cars 50 until thelock 35 overlies hook 36 and furtherthe free end 55 of the element 52 trips andis held down by latch 56.When the element 52 is held depressed by latch 56 a finger 58 thereonextends through an opening in the base 44 and engages a'leaf springelement 60 and separates thereby a pair of contacts 62. The contacts areconnected in series through the leaf element 60 across terminals-64 and66 so that when the leaf contacts 62 are closed the terminals are indirect shorting connection with one another. A heating element 68 issupported in heatdistributing relation on a bimetal element 69 andflexible leads 70 and 71 therefrom are connected to the respectiveterminals 64 and 66, so that the heating element 68 is in parallel withthe leaf spring and contacts. In effect, the terminals 64 and 66 areunder power when toaster contacts 38 are closed.

When the lock element 52 is depressed completely and held down by thelatch 56 so the finger 58 opens the contacts, the terminals connect onlyacross the bimetal heating element 68 to energize the element; in allother positions of lock element 52 the finger releases the leaf spring60 to close the'contacts 62 which short circuits across the terminals toin effect deenergize the bimetal heating element. It is at this timewhen the latch 56 is released and latch 72 engaged that the bimetalheating element is deenergized and allowed to cool down, while howeverthe toaster heating elements 20 are yet energized.

Referring now to the specific construction of the various latch elements56 and 72, the latch element 56 is pivoted at 74 to a vertical leg ofthe base, and moreover has a finger 76 that 'extends laterally of thepivot. A trigger release element 78 for actuating latch 56 is pivoted at79 to a laterally movable member 80, which member has a slot to receivepin 74 and which further fits within grooves in vertical leg of thebase. The latch finger 76 extends between spaced guides on the triggerrelease element 78 so as to tie the rotational movetoasting apparatus.The external control knob (not shown) is pivoted to rotate about a post81 secured to base leg 86, and the knob is keyed to a cam plate82 whichlikewise is supported to rotate about. the post. A pin 84 secured to thelaterally moving element is received in a cam slot 88 eccentricallydisposed relative to the post 81, so that upon rotation of the cam plate82 the pin is caused to move laterally of the post. This likewisechanges the location of the trigger element 78 relative to base leg 85.This particular control means is suitable for use by the housewife tofine-tune control the toaster cycle.

The second latch 72 is a one piece element which is pivoted about thesame pin 74 and has the upper latch configuration and a lower triggerelement 90. A single spring 92 coiled about the pin 74 biases thelatches 56 and 72 toward the locking positions normally, unless othermeans to be discussed now tend to move the latch otherwise.

THe bimetal element 69 is secured to a yoke 94 that pivotally rotates onpin 95 projecting from the base 44. A trip arm 98 is also securedrigidly to the yoke 94 so that at least at the yoke, it rotates with thebimetal. The trip arm 98 is typically formed of several components whichare adjustably mounted relative to one another but which are normallylocked tight in operation. The arm construction shown has trigger 78actuating extension element 100 which is secured adjustably to the yokeby means of a pivot rivet 102 and an ad- 'justing screw 103 threadedinto the yoke and received within a slot in the extension element.Additionally, trigger 90 actuating extension element 106 is secured tothe extension element 100 by means of a similar pivot rivet 107 andscrew 108 construction. Upstanding ears, 110 being formed from the yoke94, 111 and 112 being formed from the extension element 100, and 113being formed from extension element 106 respectively are located inpairs 110 and 111, and 112 and 113 such that a gauge can fit betweeneach pair and upon properly loosening the lock screw used to orient thecomponents angularly relative to one another.

A second'adjustment means 118 is formed by a movable element 119 holdingthe free end of the bimetal 69. Retaining element 119 thus is supportedon a leaf spring 120 which is secured as at 121 to the leg 85 of thebase 44. The spring has an opening therein cooperating threadably with ascrew element 123, which screw is supported rotatably by appropriatemeans within a slotted opening in the leg 85. A key socket on the screwpermits it to be rotated to in effect move the engagement of the screwwith the spring to shift the free end of the bimetal toward or away fromthe base leg 85. This also shifts the location of the free end of thetrip arm 98 in a like manner. The case 16 has an opening in alignmentwith the screw 123 to provide for the readyfinsertion of an adjustingtool from outside of the toaster.

It is generally noted that face 125 on extension element 100 cooperatesto engage trigger 78 upon movement of the trip lever away from the baseleg 85; while extension element 106 has a face 127 that ordinarilyengages and holds the trigger 74 in a manner that its latch 72 is in thereleased position until sufficient movement of the trip lever away fromthe base leg 85 permits the trigger to ride off the face 127 to permitthe spring 92 to move the latch 72 to its latching position overlyingthe element 52. The bimetal 69 is designed upon heating deflectio'ntomove the trip lever 98 away from the base leg 85 and upon coolingdeflection to move toward the base leg. The heating deflection of thebimetal thus will sequentially set the latch 72 and release latch 56,and cooling deflection will release the latch 72.

In this regard, the gauging between the yoke 94 and the extensionelement 100 locates the actuating face 125 of the trip arm relative tothe free end of the bimetal such that the heating deflection required ofthe bimetal can be set generally within specific broad limits. Thegauging between the extension elements 100 and 106 determines thecooling deflection required between when the first latch is tripped andthe second latch is tripped, which is known as the cooldown time. Eachsetting is preferably made by means of a specific gauge and generallycalibrates the timing mechanism to its end use appliance. It is alsopossible to provide that the latch 72 is not even set by the time thelatch 56 is released such that the lock element 52 is immediatelyreleased to permit the carriage to move to the nontoasting elevatedpositions and to deenergize boththe bimetal heating element 68 and thetoaster heating elements 20. This eliminates the cooldown cycleentirely.

Although experience dictates quite accurately the particular actualaverage times required for a proper toasting cycle,

and such can be generally satisfied by the gauge settings of the triplever 98, external adjustment is needed for more reliable control. FOrexample, the total time required for a toasting cycle, with acold-starting toaster, might be 2 minutes; where a designed initialcooldown cycle of 30 seconds is included. THe gauging of the timingmechanism can be completed to give this general control, and the toastercan be tested then. If the cycle is too long or too short, it ispossible merely by external manipulation of the screw 123 to vary theorientation of the bimetal sufficiently to bring it into the propercycle time. It is also possible to back ofi the screw after the timerequired has lapsed for causing the face to release the latch 56 at thatinstant. This latch release can be detected by an operator by means of aglow lamp or ammeter in series with the toaster because of the increasein amperes caused by the shunting across closed contacts 62 of the highresistant bimetal heating element 68. In fact, it is also possible tocalibrate an entire bank of like toasters in a single test with eachtoaster being sequentially energized at a few seconds increment wherethe operator after the required initial time lapses and going fromtoaster to toaster in the same sequence as the toasters were startedmanually releases the respective toaster latch 56.

What I claim is:

1. In a toaster having a case holding heating elements, and a breadsupport carriage movable therein between a toasting position whereat theheating elements are energized and a nontoasting position, an improvedtiming mechanism includ ing a latch effective in a locking position tohold the carriage in the toasting position and in a release position topermit the carriage to move to the nontoasting position, comprising atrigger element coupled to the latch for shifting the latch from thelocking position to the release position, a bimetal and trip meansconnected thereto to be moved thereby, means restraining the bimetalagainst movement at one location such that the trip means at a secondlocation moves toward and away from the trigger element responsive totemperature variation of the bimetal, first adjustment means for movingthe trigger element relative to the latch to adjustable distances fromthe trip means and second adjustment means for moving the bimetalrestraining means to adjustable positions whereby adjustment of eitheris effective to vary the deflection required of the bimetal to move thetrip means sufficiently to actuate the trigger element for shifting thelatch to the release position, and first and second means for adjustingthe first and second adjustment means respectively from the exterior ofthe case.

2. A timing mechanism according to claim 1, wherein the first adjustmentmeans includes an element to which the trigger element is pivoted, andmeans to support the element for movement toward and away from the tripmeans.

3. A timing mechanism according to claim 2, wherein the first means foradjusting the first adjustment means includes a cam plate and means tosupport the cam plate for rotation about an axis fixed relative to thelatch, and follower means coupled to the element and cooperating withthe cam plate to move the element responsive to rotation of the camplate.

4. A timing mechanism according to claim 1, wherein the secondadjustment means includes an element that is coupled to the bimetal atthe one location and serves as the restraining means, and means tosupport the element for movement toward and away from the triggerelement.

5. A timing mechanism according to claim 4, wherein the second means foradjusting the second adjustment means includes a screw and means torotatably support the screw to effect thread advance thereon along anaxis fixed relative the latch and in a direction transverse to theelement, and follower means coupling the screw to the element to movethe element responsive to rotation of the screw.

6. A timing mechanism according to claim 1, wherein the first adjustmentmeans includes a first element to which the trigger element is pivoted,means to support the first element for movement toward and away from thetrip means, wherein the second adjustment means includes a secondelement that is coupled to the bimetal at the one location and serves asthe restraining means, and means to support the second element formovement toward and away from the trigger element.

7. In a toaster having a case holding heating elements, and a breadsupport carriage movable therein between a toasting position whereat theheating elements are energized and a nontoasting position, an improvedtiming mechanism including a base and a latch pivoted to the baseefiective in a locking position to hold the carriage in the toastingposition and in a release position to permit the carriage to move to thenontoasting position, comprising a trigger element and a slide pivotallysupporting said trigger element, means coupling the trigger elementrotatably to the latch for shifting the latch from the locking positionto the release position upon rotation of the trigger element, a bimetaland trip means connected thereto to be moved thereby, a restrainingelement coupled to the bimetal at one location restraining movementthereof such that the trip means at a second location moves toward andaway from the trigger element responsive to temperature variation of thebimetal, means supporting the slide to move and with it carry thetrigger element relative to the latch to adjustable distances from thetrip means, means supporting the bimetal restraining element to move toadjustable positions whereby the trip means is moved correspondingly toadjustable distances from the trigger means, and first and second meansfor adjusting the positions of the slide and of the ficiently to actuatethe trigger element for shifting the latch to Y the release position.

8. A timing mechanism according to claim 7, further including a bimetalheating means, and means operable when the latch is in the lockingposition to energize the bimetal heating means.

9. A timing mechanism according to claim 7, wherein one of the first andsecond externally operable means includes a con trol element that isnormally exposed on the exterior of the case and the other of the firstand second externally operable means is provided with means including anopening in the case which permits the insertion therethrough of a toolsuitable to actuate the means.

1. In a toaster having a case holding heating elements, and a breadsupport carriage movable therein between a toasting position whereat theheating elements are energized and a nontoasting position, an improvedtiming mechanism including a latch effective in a locking position tohold the carriage in the toasting position and in a release position topermit the carriage to move to the nontoasting position, comprising atrigger element coupled to the latch for shifting the latch from thelocking position to the release position, a bimetal and trip meansconnected thereto to be moved thereby, means restraining the bimetalagainst movement at one location such that the trip means at a secondlocation moves toward and away from the trigger element responsive totemperature variation of the bimetal, first adjustment means for movingthe trigger element relative to the latch to adjustable distances fromthe trip means and second adjustment means for moving the bimetalrestraining means to adjustable positions whereby adjustment of eitheris effective to vary the deflection required of the bimetal to move thetrip means sufficiently to actuate the trigger element for shifting thelatch to the release position, and first and second means for adjustingthe first and second adjustment means respectively from the exterior ofthe case.
 2. A timing mechanism according to claim 1, wherein the Firstadjustment means includes an element to which the trigger element ispivoted, and means to support the element for movement toward and awayfrom the trip means.
 3. A timing mechanism according to claim 2, whereinthe first means for adjusting the first adjustment means includes a camplate and means to support the cam plate for rotation about an axisfixed relative to the latch, and follower means coupled to the elementand cooperating with the cam plate to move the element responsive torotation of the cam plate.
 4. A timing mechanism according to claim 1,wherein the second adjustment means includes an element that is coupledto the bimetal at the one location and serves as the restraining means,and means to support the element for movement toward and away from thetrigger element.
 5. A timing mechanism according to claim 4, wherein thesecond means for adjusting the second adjustment means includes a screwand means to rotatably support the screw to effect thread advancethereon along an axis fixed relative the latch and in a directiontransverse to the element, and follower means coupling the screw to theelement to move the element responsive to rotation of the screw.
 6. Atiming mechanism according to claim 1, wherein the first adjustmentmeans includes a first element to which the trigger element is pivoted,means to support the first element for movement toward and away from thetrip means, wherein the second adjustment means includes a secondelement that is coupled to the bimetal at the one location and serves asthe restraining means, and means to support the second element formovement toward and away from the trigger element.
 7. In a toasterhaving a case holding heating elements, and a bread support carriagemovable therein between a toasting position whereat the heating elementsare energized and a nontoasting position, an improved timing mechanismincluding a base and a latch pivoted to the base effective in a lockingposition to hold the carriage in the toasting position and in a releaseposition to permit the carriage to move to the nontoasting position,comprising a trigger element and a slide pivotally supporting saidtrigger element, means coupling the trigger element rotatably to thelatch for shifting the latch from the locking position to the releaseposition upon rotation of the trigger element, a bimetal and trip meansconnected thereto to be moved thereby, a restraining element coupled tothe bimetal at one location restraining movement thereof such that thetrip means at a second location moves toward and away from the triggerelement responsive to temperature variation of the bimetal, meanssupporting the slide to move and with it carry the trigger elementrelative to the latch to adjustable distances from the trip means, meanssupporting the bimetal restraining element to move to adjustablepositions whereby the trip means is moved correspondingly to adjustabledistances from the trigger means, and first and second means foradjusting the positions of the slide and of the bimetal restrainingelement each operable from the exterior of the case, whereby adjustmentof either is effective to vary the deflection required of the bimetal tomove the trip means sufficiently to actuate the trigger element forshifting the latch to the release position.
 8. A timing mechanismaccording to claim 7, further including a bimetal heating means, andmeans operable when the latch is in the locking position to energize thebimetal heating means.
 9. A timing mechanism according to claim 7,wherein one of the first and second externally operable means includes acontrol element that is normally exposed on the exterior of the case andthe other of the first and second externally operable means is providedwith means including an opening in the case which permits the insertiontherethrough of a tool suitable to actuate the means.